40 NEW CALIFOENIAN STAMPS AT DOLCOATH. 



The engine is of the modern girder type, compound 

 horizontal and jet condensing, coupled at right angles with 

 heavy fly wheel between. The cylinders are 15^ and 27 inches 

 respectively, and 4 feet stroke, fitted with metallic pistons and 

 expansion valves on back of main slides, adjustable by hand 

 whilst the engine is running. Each cylinder is fitted with steam 

 auxiliary at either end, so that the engine can be easily started 

 in any position with full load on. The engine is controlled by a 

 Tangye's high speed governor to run at a speed of 48 revolutions 

 per minute, being equal to a piston speed of 384 feet per 

 minute. Steam is raised by two Cornish boilers, each 6 feet 

 diameter and 30 feet long, with tubes 3 feet G-in. diameter 

 strengthened by Bowling expansion rings, the ends being each 

 in one plate flanged and gussetted, and the shell double rivetted 

 longitudinally — all made with Siemen Martin mild steel, 

 constructed for a working pressure of 100-lbs. per square inch 

 and tested to 200-lbs. All the mountings and pipes are extra 

 strong to match. The boilers are fed by a steam donkey engine 

 with cold water supplied by the Camborne Water Company. 

 The same boilers supply steam to Messrs. Holman Brothers' 

 engine, which pumps water from the adit for condensing and 

 tin dressing, and also to a small Tangye's engine for electric 

 lighting. 



The chief advantages of this New Stamps over the Cornish 

 may be summed up in a few brief sentences. 



The steam is worked at 100-lbs. pressure instead of about 

 40-lbs., so that the engine works much more economically. 



The cam shafts with cams for lifting the heads not being 

 more than about one-fifth the weight of the huge iron axles and 

 cams in the Cornish stamps for a similar output, a much less 

 power is required to turn the axles. 



The heads being circular and revolving at every lift, they 

 wear much more evenly and consequently do much more effective 

 work. 



The wear and tear of the heads and lifters and of most of 

 the other working parts of the stamps is much less than in the 

 old stamps. The friction is also considerably lessened. 



